Paper and paper coating products produced using multi-phase calcium silicate hydrates

ABSTRACT

A paper composition including multiphasic calcium silicate hydrate fillers. Multi-phase calcium silicate hydrates, having unique physical and chemical properties, are prepared by hydrothermal reaction of specified ratios of CaO and SiO2, normally starting from slurries of slaked lime and from fluxed calcined diatomaceous earth, each of which is at about the atmospheric boiling point before being mixed and charged to a reactor, and pressurized. The hydrothermal reaction is carried out while maintaining the initial dilution for a preselected reaction time at a preselected reaction temperature. The calcium silicate hydrates have high water absorption and light scattering power, and have optical and physical properties making them highly desirable as a filler in papermaking.

RELATED PATENT APPLICATIONS

This application is a Divisional of co-pending allowed U.S. applicationSer. No. 09/649,413 filed Aug. 26, 2000, assigned U.S. Pat. No.6,726,807,to be issued on Apr. 27, 2004, which claimed priority under 35USC § 119 (e) from U.S. Provisional Application Ser. No. 60/150,862filed on Aug. 26, 1999, the disclosures of each of which areincorporated herein by their entirety by this reference.

COPYRIGHT RIGHTS IN THE DRAWING

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The applicant has no objectionto the facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the Patent and Trademark Officepatent file or records, but otherwise reserves all copyright rightswhatsoever.

TECHNICAL FIELD

This invention relates to novel paper products, paper coatings, andpigment products, made using calcium silicate hydrate (“CSH”)crystalline structures.

BACKGROUND

The paper industry currently utilizes many different types of fillers asa substitute for pulp fiber, as well as to provide desired functionaland end-use properties to various paper and paper products. For example,clay has long been used as a filler or fiber substitute. Importantly,the use of clay also provides an improvement in print quality. However,one disadvantage of clay is that it is relatively low in brightness.And, the use of clay in papermaking leads to a decrease in tensilestrength of the paper sheet, and to reductions in paper sheet caliperand stiffness.

Calcined clay was introduced to the paper industry in an effort toimprove brightness and opacity in paper. However, one significanteconomic limitation of calcined clay is that it is relatively expensive.Also, physically, calcined claim is highly abrasive.

Titanium dioxide, TiO₂, is another example of a filler commonly used inpapermaking. Most commonly, titanium dioxide is used to improve opacityof the paper sheet, and, in some cases, it is used to improve sheetbrightness as well. Use of titanium dioxide is limited, though, becauseit is extremely expensive. Unfortunately, it is also the most abrasivepigment on the market today. This is important because highly abrasivepigments are detrimental in the paper industry since they wear downcritical paper machine components, such as forming wires, printing pressplates, and the like, ultimately leading to high life cycle costs due tothe constant repair and maintenance costs.

When calcined clay was first introduced, it was touted as a titaniumdioxide extender. Although it did succeed in extending TiO₂, it isnonetheless abrasive, and it is more expensive than either standard clayor market pulp fiber.

More recently, and particularly since the mid 1980's, ground calciumcarbonate (GCC) has been used as a low cost alkaline filler. AlthoughGCC improved sheet brightness, one downside to GCC was that it too isabrasive. Moreover, use of GCC reduces tensile strength, caliper andstiffness of paper sheets. Consequently, a paper sheet containing GCCtends to be rather limp.

Finally, one of the most commonly used alkaline paper fillers isprecipitated calcium carbonate(PCC). PCC is presently one of the bestcompromise solutions for providing a high brightness filler at aneconomically feasible price. However, a significant downside to the useof PCC in paper sheets is that PCC provides a lower light scatteringpower than either TiO₂ or calcined clay. Also, it often reduces sheetstrength and stiffness.

Thus, the paper industry still has an unmet need, and continues to lookfor, a multi-functional pigment that can simultaneously provide two ormore of the following attributes:

-   -   a) cost that are less than TiO₂;    -   b) better optical properties than calcined clay;    -   c) better optical properties than GCC;    -   d) better optical properties than PCC;    -   e) minimal tensile strength loss associated with increased        filler usage;    -   f) at least some improved strength characteristics, such as        sheet stiffness.

In addition to the just stated criteria, if a paper filler could alsosimultaneously improve sheet porosity (i.e., provide a more closedsheet) yet provide higher sheet caliper, it would be a very highlydesired filler material. To date, no single paper filler with suchattributes has been brought to the market. Consequently, the developmentand commercial availability of such a filler would be extremelydesirable.

Finally, the current industry demand for printing papers, especially therapidly increasing demand for ink jet paper, requires a high performancepaper. The performance of such paper would be enhanced by theavailability of a pigment that would provide excellent water and oilabsorption capacities, so that the paper could quickly capture andprevent ink from spreading or bleeding, as well as aid in surface dryingof the ink.

Some of the key requirements for an ideal papermaking pigment can besummarized as set forth in Tables 1, 2 and 3 below: TABLE 1 IdealizedPaper Filler Attributes Sheet Opacity Filler Sheet Brightness AttributeScattering Scattering Coefficient Power Industry HIGHER HIGHER HIGHEREQUAL OR Requirement than pulp than pulp than pulp HIGHER or or or thanpulp carbonate carbonate carbonate or fillers fillers fillers carbonatefillers

TABLE 2 Key strength parameters for an “Ideal” pigment. Sheet CaliperBulk Porosity Sheet Stiffness Tensile Attribute Smoothness IndustryHIGHER HIGHER HIGHER HIGHER HIGHER HIGHER Requirement than than thanthan pulp than pulp than pulp pulp pulp pulp sheet sheet sheet sheetsheet sheet alone or alone or alone or alone alone alone with with withor with or with or with CaCO₃ CaCO₃ CaCO₃ CaCO₃ CaCO₃ CaCO₃ fillersfillers fillers fillers fillers fillers

TABLE 3 Key printing requirements for an “Ideal” pigment. SheetAttribute Ink Penetration Show Through Print Through Industry LOWER thanLOWER than LOWER than Requirement pulp sheet alone pulp sheet alone pulpsheet alone or with CaCO₃ or with CaCO₃ or with CaCO₃ filler fillerfiller

Currently, the papermaking industry uses various combinations ofavailable fillers in order to optimize the properties as may be desiredin a particular papermaking application. However, because currentlyavailable fillers reduce sheet strength to at least some extent, theindustry relies on strength additives, such as starch and/or polymers,to maintain the desired paper strength properties when fillers areutilized. Unfortunately, because different pigments have differentparticle charge characteristics, additions of multiple pigments andadditives in the paper making system often create an extremelycomplicated chemical system which may be somewhat sensitive anddifficult to control.

In summary, there remains a significant and as yet unmet need for a highquality, cost effective filler which can be used to simultaneouslyachieve desired optical properties and sheet strength in paper products.Further, there remains a continuing, unmet need for a method to reliablyproduce such a pigment which has desirable optical properties and whichprovides significant cost benefits when compared to the use of titaniumdioxide or other pigments currently utilized in the production of paper.

OBJECTS, ADVANTAGES AND NOVEL FEATURES

Accordingly, an important objective of my invention is to provide aprocess for the manufacture of unique calcium silicate hydrate (“CSH”)products, which provide crystalline structures with desired brightness,opacity, and other optical properties.

Another important and related objective is to provide an economicalsubstitute for current paper fillers such as titanium dioxide.

A related and important objective is to provide a method for theproduction of novel paper products using my unique calcium silicatehydrate product.

An important objective is to provide a new calcium silicate hydrateproduct with low bulk density, good chemical stability (particularly inaqueous solutions), and a high adsorptive capability, among otherproperties.

These and other advantages, and novel features of my multi-phase calciumsilicate hydrates, the method for their preparation, and the improvedpigments and paper products produced therewith will become evident andmore fully appreciated from full evaluation and consideration of thefollowing detailed description, as well as the accompanying tables anddrawing figures.

SUMMARY

I have now discovered the process conditions required to reliablyproduce unique calcium silicate hydrate products with particularlyadvantageous properties for use as a filler in papermaking. The productsare produced by reacting, under hydrothermal conditions, a slurry ofburned lime (quick lime) and a slurry of fluxed calcined diatomaceousearth (or other appropriate starting siliceous material). Preferably, afine slurry of each of the lime and the fluxed silica are utilized.

For one of my CSH products, the lime slurry is prepared by providingabout 1.54 pounds of suspended solids per gallon of lime slurry. Thesilica slurry is prepared by providing about 1.55 pounds of suspendedsolids per gallon of water. The slaking of the lime slurry raises thetemperature of the slurry to near the boiling point; this isaccomplished before adding the same to the fluxed silica. The slurry offluxed calcined diatomaceous earth is heated to near the boiling point,also, before it is mixed with the lime slurry. When both slurries arenear atmospheric boiling point conditions, then they are mixed togetherand stirred, while being retained under pressure in an autoclave orsimilar reactor. Temperature of the reaction slurry is raised to betweenabout 245° C. and 260° C., and the reaction is continued for about twohours, more or less. The CaO/SiO2 ratio is maintained, in the feedmaterials, of about 1.35 (± about 0.10) moles CaO to 1 mole of SiO2.After the reaction is completed, the product is cooled before thepressure is released and the product crystals are harvested.

Generally, the product of the above described reaction is a multi-phasemixture (i.e., two different forms or phases are present in theproduct), predominantly of foshagite, with some xonotlite. Importantly,small, haystack like particles containing complex multi-phasecrystalline optical fibers are produced that can be advantageouslyemployed in papermaking for coating and for wet end fillers. However,the hydrothermally produced multi-phase crystalline optical fibers arevastly improved over previously produced hydrothermal calcium silicatehydrates of which I am aware, at least with respect to their physicalproperties, their optical properties, and their utility as a filler inpapermaking. Moreover, my unique CSH products are suitable for multipleend uses, such as filler for value added papers, for commodity papers,for newsprint, paper coating applications, as well as for paints, rubbercompositions, and other structural materials.

It is important to appreciate that my hydrothermal process for themanufacture of my unique multiple phase calcium silicate hydrates(“CSH's”), including my novel multi-phase mixture of foshagite andxonotlite, (CaO₄(SiO₃) (OH)₂ and C₆Si₆O₁₇(OH)₂, respectively) results ina unique mixture of calcium silicate hydrates which have a unique anddistinct X-ray diffraction pattern.

Further, the variables that affect the chemical composition of my CSHproducts, and the primary and secondary structure of the CSH particlesand their characteristic properties, can be affected, among otherthings, by (a) the CaO/SiO₂ mole ratio, by (b) concentration of the CaOand of the SiO₂ in the reaction slurry, (c) the reaction temperature,and (d) the reaction time. By manipulating the just mentioned variables,I have been able to develop two novel pigment products. Those twoproducts can be generally described as follows:

-   -   (1) A multi-phase calcium silicate hydrate having a primary        phase of foshagite, and a secondary phase of xonotlite. I refer        to this product as “TiSil” brand calcium silicate hydrate; and    -   (2) A multi-phase calcium silicate hydrate complex having a        primary phase fraction of riversideite with a minor phase        fraction of xonotlite. I refer to this product as “StiSil” brand        calcium silicate hydrate.

The first product is formed with a high CaO to SiO₂ mole ratio (about a1 to 1, to about a 1.7 to 1 ratio of CaO to SiO2), at a high temperature(˜200° C.-300° C.), with a low final slurry concentration (˜0.4-0.6 lbof solids per gallon of slurry), and with a reaction time ofapproximately 2 hours. It has a characteristic X-ray diffraction patternas shown in FIG. 1. The scanning electron micrographs (“SEMs”) of thisproduct are shown in FIGS. 2 and 3. As is evident from the SEMs, thisproduct consists of primary, fibrous particles joined together, andthus, produces a secondary, three dimensional, “hay-stack” structure.The physio-chemical characteristics of this product are unique. Forexample, extremely high water absorption is provided. This pigment alsoprovides unique paper properties when utilized in papermaking. Forexample, this pigment, when used as a filler, can improve the opticalproperties along with sheet strength, sheet bulk, sheet smoothness, andsheet porosity, simultaneously.

The second product is formed by reacting lime and silica with a lowmole-ratio (about a 0.85 to 1 ratio of CaO to SiO2), a low reactiontemperature (˜180° C. to 190° C.), at a high final slurry concentration(˜0.7-1.0 pounds of solids per gallon of slurry), and with a reactiontime of approximately 2 hours. This calcium silicate is quite differentfrom the first product just mentioned above and its unique X-raydiffraction pattern is given in FIG. 4. The scanning electronmicrographs (SEMs) for this product are given in FIGS. 5 and 6. As theSEMs indicate, this product consists of some fibrous growths that inturn grow randomly and almost continuously to provide an irregularglobular structure. This product is uniquely formulated to provide ultrahigh sheet stiffness when it is used as a filler in paper.

In summary, the unique features of these hydrothermally produced calciumsilicate hydrate products include:

-   -   a unique crystallo-chemical composition    -   a multi-phase crystal system    -   a primary and secondary fibrous particle structure    -   a high water absorptivity (in the ˜300%-1000% range).

The result of the unique properties and physical structure enable theseunique CSH products to provide a combination of beneficial properties topaper products in a manner heretofore unknown by paper fillers. Forexample, the use of these products in paper can increase sheet bulk andGurley porosity, simultaneously. In addition, these products are made upof large particles, but the products can still scatter light better thanPCC, GCC, clay, or even calcined clay.

BRIEF DESCRIPTION OF THE DRAWING

The patent or application file contains at least one black and whitephotograph as a drawing. Copies of this patent or patent applicationpublication with black and white drawing(s) will be provided by the U.S.Patent and Trademark Office upon request and payment of the necessaryfee.

In order to enable the reader to attain a more complete appreciation ofthe invention, and of the novel features and the advantages thereof,attention is directed to the following detailed description whenconsidered in connection with the accompanying drawing, wherein:

FIG. 1 illustrates the characteristic X-ray diffraction pattern of oneembodiment of the present invention, where foshagite and xonotlite arepresent.

FIG. 2 is a scanning electron micrograph (“SEM”) (at10,000×magnification) of the product described by the X-ray diffractionpattern just set forth in FIG. 1, showing in detail the primary, fibrousparticles which are joined together.

FIG. 3 is a scanning electron micrograph (“SEM”) (at 2000×magnification)of the product described by the X-ray diffraction pattern just set forthin FIG. 1 and also just illustrated in FIG. 2, now showing how theprimary, fibrous particles are joined together, producing a secondary,three dimensional, “hay-stack” structure.

FIG. 4 illustrates the characteristic X-ray diffraction pattern ofanother embodiment of the present invention, where riversideite andxonotlite are present.

FIG. 5 is a scanning electron micrograph (“SEM”) (at10,000×magnification) of the product described by the X-ray diffractionpattern just set forth in FIG. 4, showing in detail the globularparticles which are provided.

FIG. 6 is a scanning electron micrograph (“SEM”) (at 2000×magnification)of the product described by the X-ray diffraction pattern just set forthin FIG. 4 and also just illustrated in FIG. 5, now showing details ofseveral particles.

FIG. 7 illustrates the solubility of lime in water as a function oftemperature.

FIG. 8 illustrates the solubility of various forms of silica in water asa function of temperature.

FIG. 9 illustrates one heating and cooling cycle which has been found tobe advantageous for reaction conditions suitable for formation of the“TISIL™” brand product described in FIGS. 1, 2, and 3 above.

FIG. 10 is a comparison of sheet brightness as a function of percentfiller, when using as filler either a commercial precipitated calciumcarbonate (PCC) or the novel calcium silicate hydrate (“TISIL™” brand)product described herein.

FIG. 11 is a comparison of sheet opacity results as a function ofpercent filler when using as filler either a commercial precipitatedcalcium carbonate (PCC) or the novel calcium silicate hydrate (“TISIL™”brand) product described herein.

FIG. 12 is a comparison of sheet scattering coefficient results as afunction of percent filler when using as filler either a commercialprecipitated calcium carbonate (PCC) or the novel calcium silicatehydrate (“TISIL™” brand) product described herein.

FIG. 13 is a comparison of filler scattering coefficient results as afunction of percent filler between commercial precipitated calciumcarbonate (PCC) and the novel calcium silicate hydrate (“TISIL™” brand)product described herein.

FIG. 14 provides a comparison of paper sheet stiffness as a function ofpercent filler, between a commercial precipitated calcium carbonate(PCC) and the novel calcium silicate hydrate (“TISIL™ ” brand) productdescribed herein.

FIG. 15 provides a comparison of paper sheet bulk as a function ofpercent filler, between a commercial precipitated calcium carbonate(PCC) and the novel calcium silicate hydrate (“TISIL™” brand) productdescribed herein.

FIG. 16 provides a comparison of paper sheet porosity as a function ofpercent filler, between a commercial precipitated calcium carbonate(PCC) and the novel calcium silicate hydrate (“TISIL™” brand) productdescribed herein.

FIG. 17 provides a comparison of paper sheet tensile index as a functionof percent filler, between a commercial precipitated calcium carbonate(PCC) and the novel calcium silicate hydrate (“TISIL™” brand) productdescribed herein.

FIG. 18 provides a comparison of paper sheet brightness as a function ofpercent filler, between (a) the combination of a commercial precipitatedcalcium carbonate (PCC) and titanium dioxide, and (b) the novel calciumsilicate hydrate (“TISIL™” brand) product described herein.

FIG. 19 provides a comparison of paper sheet opacity as a function ofpercent filler, between (a) the combination of a commercial precipitatedcalcium carbonate (PCC) and titanium dioxide, and (b) the novel calciumsilicate hydrate (“TISIL™” brand) product described herein.

FIG. 20 provides a comparison of paper sheet scattering coefficient as afunction of percent filler, between (a) the combination of a commercialprecipitated calcium carbonate (PCC) and titanium dioxide, and (b) thenovel calcium silicate hydrate (“TISIL™” brand) product describedherein.

FIG. 21 provides a comparison of filler scattering coefficient, between(a) the combination of a commercial precipitated calcium carbonate (PCC)and titanium dioxide, and (b) the novel calcium silicate hydrate(“TISIL™” brand) product described herein.

FIG. 22 provides a comparison of paper sheet stiffness as a function ofpercent filler, between (a) the combination of a commercial precipitatedcalcium carbonate (PCC) and titanium dioxide, and (b) the novel calciumsilicate hydrate (“TISIL™” brand) product described herein.

FIG. 23 provides a comparison of paper sheet bulk as a function ofpercent filler, between (a) the combination of a commercial precipitatedcalcium carbonate (PCC) and titanium dioxide, and (b) the novel calciumsilicate hydrate (“TISIL™” brand) product described herein.

FIG. 24 provides a comparison of paper sheet porosity as a function ofpercent filler, between (a) the combination of a commercial precipitatedcalcium carbonate (PCC) and titanium dioxide, and (b) the novel calciumsilicate hydrate (“TISIL™” brand) product described herein.

FIG. 25 provides a comparison of paper sheet tensile index as a functionof percent filler, between (a) the combination of a commercialprecipitated calcium carbonate (PCC) and titanium dioxide, and (b) thenovel calcium silicate hydrate (“TISIL™” brand) product describedherein.

FIG. 26 provides a comparison of paper sheet opacity as a function ofash level, between (a) a commercial calcium silicate (“BULKITE™” brand)and (b) the novel calcium silicate hydrate (“TISIL™” brand) productdescribed herein.

FIG. 27 provides a comparison of paper sheet scattering coefficient as afunction of ash level, between (a) a commercial calcium silicate(“BULKITE™” brand) and (b) the novel calcium silicate hydrate (“TISIL™”brand) product described herein.

FIG. 28 provides a comparison of filler scattering coefficient as afunction of ash level between (a) a commercial calcium silicate(“BULKITE™” brand) and (b) the novel calcium silicate hydrate (“TISIL™”brand) product described herein.

FIG. 29 a comparison of paper sheet brightness as a function of ashlevel, between (a) a commercial calcium silicate (“BULKITE™” brand) and(b) the novel calcium silicate hydrate (“TISIL™” brand) productdescribed herein.

FIG. 30 provides a comparison of paper sheet porosity as a function ofash level, between (a) a commercial calcium silicate (“BULKITE™” brand)and (b) the novel calcium silicate hydrate (“TISIL™” brand) productdescribed herein.

FIG. 31 provides a comparison of the normalized paper sheet opacity(interpolated to six (6) percent ash), when using various fillers,namely (a) a commercial calcium silicate (“HUBERSIL®” brand), or (b) acommercial calcium carbonate (“HUBER® Carbonate” brand), or (c) thenovel calcium silicate hydrate (“TISIL™” brand) product describedherein.

FIG. 32 provides a comparison of the sheet ink penetration results onnewsprint sheets containing various fillers, interpolated to six (6)percent ash, showing the ink penetration when the newsprint wasmanufactured using (a) a commercial calcium silicate (“HUBERSIL®”brand), (b) a commercial calcium carbonate (“HUBER® Carbonate” brand) ,or (c) the novel calcium silicate hydrate (“TISIL™” brand) productdescribed herein.

FIG. 33 provides a comparison of the paper sheet show through results onnewsprint sheets containing various fillers, interpolated to six (6)percent ash, showing the sheet show through results when the newsprintwas manufactured using (a) a commercial calcium silicate (“HUBERSIL®”brand) , (b) a commercial calcium carbonate (“HUBER® Carbonate”), or (c)the novel calcium silicate hydrate (“TISIL™” brand) product describedherein.

FIG. 34 provides a comparison of the paper sheet print through resultson newsprint sheets containing various fillers, interpolated to six (6)percent ash, showing the sheet print through results when the newsprintwas manufactured using (a) a commercial calcium silicate (“HUBERSIL®”brand), (b) a commercial calcium carbonate (“HUBER® Carbonate” brand),or (c) the novel calcium silicate hydrate (“TISIL™” brand) productdescribed herein.

FIG. 35 provides a comparison of the Gurley sheet porosity results onnewsprint sheets containing various fillers, interpolated to six (6)percent ash, showing the sheet porosity when the newsprint wasmanufactured using (a) a commercial calcium silicate (“HUBERSIL®”brand), (b) a commercial calcium carbonate (“HUBER® Carbonate” brand),or (c) the novel calcium silicate hydrate (“TISIL™” brand) productdescribed herein.

FIG. 36 provides a comparison of the sheet tensile index results onnewsprint sheets containing various fillers, interpolated to six (6)percent ash, showing the sheet tensile index results when the newsprintwas manufactured using (a) a commercial calcium silicate (“HUBERSIL®”brand), (b) a commercial calcium carbonate (“HUBER® Carbonate” brand),or (c) the novel calcium silicate hydrate (“TISIL™” brand) productdescribed herein.

FIG. 37 provides a comparison of the Gurley sheet stiffness results onnewsprint sheets containing various fillers, interpolated to six (6)percent ash, showing the sheet stiffness when the newsprint wasmanufactured using (a) a commercial calcium silicate (“HUBERSIL®” brand), (b) a commercial calcium carbonate (“HUBER® Carbonate” brand), or (c)the novel calcium silicate hydrate (“TISIL™” brand) product describedherein.

FIG. 38 provides a comparison of the sheet static coefficient offriction results on newsprint sheets containing various fillers,interpolated to six (6) percent ash, showing the sheet staticcoefficient of friction when the newsprint was manufactured using (a) acommercial calcium silicate (“HUBERSIL®” brand), (b) a commercialcalcium carbonate (“HUBER® Carbonate” brand), or (c) the novel calciumsilicate hydrate (“TISIL™” brand) product described herein.

FIG. 39 provides a comparison of the Sheffield sheet smoothness resultson newsprint sheets containing various fillers, interpolated to six (6)percent ash, showing the sheet Sheffield sheet smoothness when thenewsprint was manufactured using (a) a commercial calcium silicate(“HUBERSIL®” brand), (b) a commercial calcium carbonate (“HUBER®Carbonate” brand), or (c) the novel calcium silicate hydrate (“TISI™”brand) product described herein.

The foregoing figures, being merely exemplary, contain various aspects,properties, and elements that may be present or omitted from actualproduct implementations depending upon the circumstances. An attempt hasbeen made to provide the figures in a way that illustrates at leastthose aspects and properties that are significant for an understandingof the various embodiments and aspects of the invention. However,variations in the illustrated aspects, elements, and properties,especially as applied for maximizing different variations of thefunctional properties illustrated, may be utilized in variousembodiments in order to provide an advantageous calcium silicate hydratefiller for various uses in the manufacture of paper.

DETAILED DESCRIPTION

In order to prepare my unique calcium silicate hydrates (“CSH”)products, it is first necessary to prepare a source of calcium. This isnormally accomplished by the formation of a slurry of calcious material,most commonly lime. However, there are several different sources ofcalcium, which may be used. Some examples are CaCO₃, CaCl₂, and hydratedlime. I have found it advantageous to employ pebble lime, if less than ½inch dimension. First, the CaO was slaked in water. The amount and therate of addition of lime were set and maintained in order to obtain adesired concentration of lime slurry. Because the slaking of lime is anexothermic process, it was necessary to control both the rate ofaddition of lime and the quantity of water used. When slaking, the besttemperature was determined to be near boiling, i.e., close to 100° C.(212° F.) in order to form lime particles as fine as possible. Once theslaking was complete, the lime slurry was then screened through a 200mesh screen to remove any grit and oversized particles. The screened andslaked lime slurry was tested for available lime (as CaO) and thentransferred to an autoclave.

The chemistry of the slaking process can be given as follows:CaO+H₂O→Ca(OH)₂  (1)(solid) (aqueous)Ca(OH)

→Ca⁺⁺+2OH⁻  (2)(aqueous)

The solubility of calcium hydroxide slurry is inversely proportional tothe temperature, as indicated in FIG. 7.

Next, it is necessary to prepare a slurry of siliceous material (i.e., aSiO2 slurry). Various siliceous materials such as quartz, water glass,clay, pure silica, natural silica (sand), diatomaceous earth, fluxedcalcined diatomaceous earth, or any combination thereof may be utilizedas a source of siliceous material. I prefer to utilize an ultra finegrade of fluxed, calcined diatomaceous earth. This raw material wasprepared into a slurry of ˜1.55 lbs of solids per gallon water. Theslurry was then preheated to near boiling, i.e., near 100° C.

Importantly, the solubility of silica (unlike that of Ca(OH)₂), isdirectly proportional to temperature, as seen in FIG. 8. For example,quartz (line A in FIG. 8) is only slightly soluble up to 100° C. From100° C. to 130° C., it starts solubilizing and around 270° C., itreaches its maximum solubility of about 0.07%.

The dissolution of silica can be represented as follows:(SiO₂)_(n)+2n(H₂O)→nSi(OH)₄  (3)

The solubility of silica can be increased by raising the pH, and/or byusing various additives (i.e. sodium hydroxide). In addition the rate ofsilica solubility is also a function of particle size, thus to enhancesolubilization of the silica, I prefer to utilize ultra fine fluxedcalcined diatomaceous earth.

Next, the siliceous slurry was mixed with the lime slurry in anautoclave, to achieve a hydrothermal reaction of the two slurries.Important, the amount of CaO in the lime slurry and the amount of SiO₂in the fluxed calcined diatomaceous earth slurry were pre-selected toprovide a predetermined CaO/SiO₂ mole ratio. Also, the concentration ofthe two slurries (CaO and SiO₂) was selected so that the finalconcentration of the reaction mixture in the autoclave falls betweenabout 0.2 pounds of solid per gallon of slurry to about 1.0 pounds ofsolid per gallon of slurry.

The hydrothermal reaction itself was carried out in a pressurizedvessel, with three major steps:

-   -   (1) Heating the slurry to the desired temperature (e.g. 180° C.        to 300° C.)    -   (2) Reacting at temperature for a specified time (e.g. 60        minutes to 240 minutes).    -   (3) Stopping the reaction and cooling down

In my laboratory, the reaction autoclave was cooled by passing quenchingwater through an internal cooling coil, or by utilizing an externaljacketed cooling system. I prefer to utilize a cool down process of fromapproximately 25 to 30 minutes to drop the temperature from about 230°C. to about 80° C., as indicated in FIG. 9.

The process steps just mentioned are very important. This is because Ihave utilized the inverse solubilities of lime and silica with respectto temperature and time in an effort to produce the desired reactioncomposition, to arrive at the desired multi-phase calcium silicatehydrate product.

Without limiting my invention to any particular theory, I can postulatethe following reaction during the hydro-thermal reaction betweencalcious material and siliceous material. First, during the heatingprocess, very few free Ca⁺⁺ ions are available. After 100° C., thesilica starts going into a gel stage. Beyond 130° C., the silica ionsbecome available for reacting. As the temperature nears 180° C., thecalcium ion Ca⁺⁺ reacts with the Si⁺ ion to form a metal silicate. Thereaction can be written as follows:x[Ca⁺⁺+2OH⁻ ]+y[Si(OH)₄]→CaO_(x)(SiO₂)_(y)+(x+y)H₂O  (4)Where:

-   -   x=1 to 6    -   y=1 to 6

The solid Ca(OH)₂ particles react with SiO₂ in the gel phase to give acalcium silicate hydroxide whose crystallo-chemical structure can bewritten as Ca₆Si₆O₁₇(OH)₂ (Xonotlite). As the temperature is furtherraised from 180° C. to 250° C., calcium silicate hydride condenses withthe remaining Ca(OH)₂ particles to give yet another calcium silicatehydroxide, this time with a distinct X-ray diffraction pattern and acrystallo-chemical formula of CaO₄(SiO₃)₃(OH)₂ (Foshagite)

Further, I have developed my hydrothermal reaction process so that morethan one unique calcium silicate hydrate can be produced. In thisrespect, it is important to note that the following variables arecritical in producing a desired end product:

-   -   1) Slaking Temperature    -   2) CaO/SiO₂ mole ratio    -   3) Slurry Concentration    -   4) Reaction Temperature    -   5) Reaction Time at Temperature

By changing these variables, a product having several different phasesof calcium silicate hydroxide can be produced. Some of these phases mayinclude: Morphol- X-ray Diffraction peaks Formula ogy Major MinorCa₄(SiO₃)₃(OH)₂ Foshagite d = 2.93 Å, d = 2.16 Å, d = 4.96 Å Ca₆Si₆O₁₇Xonotlite d = 3.02 Å, d = 2.04 Å, d = 8.50 Å Ca₅Si₆O₁₇(OH)₂ River- d =3.055 Å, d = 3.58 Å, d = 2.80 Å sideite

Although not normally important, one should note that my final productCSH composition may also contain minor amounts of calcite-aragonite,produced as a result of side reactions.

The first and most important product of my process is a multi-phase CSHcomposition having various amounts of phases of matter represented byCaO₄ (SiO₃)₃ (OH)₂ (Foshagite) and Ca₆Si₆O₁₇(OH)₂ (Xonotlite). A uniqueX-ray diffraction pattern for this product is provided in FIG. 1. Inthat XRD, the crystallochemical formula of the mixture, and thecharacteristic d spacings, are given below:Foshagite, CaO₄ (SiO₃)₃ (OH)₂ d=2.97 Å, d=2.31 Å, d=5.05 Å  (Phase I)Xonotlite, Ca₆Si₆O₁₇(OH)₂ d=3.107 Å, d=1.75 Å, d=3.66 Å  (Phase II)

The Scanning Electron Micrographs (“SEMs”) representing this firstproduct are provided in FIGS. 2 and 3. As shown in FIGS. 2 and 3, it isimportant to note that the product consists of primary particles andsecondary particles. The primary particles have a diameter between 0.1and 0.2 microns and a length between 1.0 and 4.0 microns. FIG. 3 alsoindicates that the primary particle has two phases. The rod or ribbonlike structure is characteristic of xonotlite (Ca₆Si₆O₁₇(OH₂)) while thepredominant structures are thin and fibrous, characteristic of foshagite(Ca₄(SiO₃)₃(OH) ₂). The diameter of the foshagite crystals ranges from0.1 to 0.3 microns and the length is ranges from 2.0 to 5.0 microns.

The SEM of FIG. 3 reveals a secondary, three dimensional structure. Thisthree dimensional structure is believed to be formed by the interlockingof the fibrous material and the continuous growth of the “gel” likematerial at the intersection of the individual particles. This may alsobe the reason that the secondary structure is fairly stable.Importantly, the secondary structure can generally withstand the shearforces encountered during the discharge of material from pressurevessels after the reaction has completed, as well as shear forcesencountered during papermaking. This is seen, for example, in that thesecondary structure maintains its “bulk density” during some of the enduse processes such as calendering during paper making. The particle sizeof secondary structure, as measured by particle size measuring deviceslike the Malvern Mastersizer, is in the range of 10-40 microns.

The calcium silicate hydroxide mixture of my invention also has veryhigh brightness characteristics. A comparison with other pigments isgiven below:

Various pigments and their typical published brightness values are asfollows: Pigment GE (TAPPI) Brightness (%) Calcium Silicate Hydrate95-97 (TiSil Brand CSH) Calcined (High Brightness) 89-91 Clay FillerClay 85-88 Synthetic Silica  97-100 Calcium Carbonate 95 ± 1 

One of the most significant characteristics of the composition of matterproduced by my process is the ability of these multiple phase calciumsilicates to absorb large amounts of water. These calcium silicates canadsorb anywhere from 350% to 1000% of their weight. This high waterabsorption capacity makes my pigment extremely well suited forpreventing ink strike through in writing and printing papers, newsprintand more.

EXAMPLE 1 Manufacture of Multiple Phase Silicate Hydrates (5XPC 12)

Initially, 135.09 grams of ½″ rotary pebble lime (Mississippi Lime Co.)was accurately weighed and slaked in 410 milliliters of de-ionizedwater. The slaking reaction is exothermic and caused the slurrytemperature to rise to near boiling. When the slurry temperature wasvery near boiling and before much of the water had evaporated, anadditional 1190 milliliters of water was added to both dilute and coolthe slurry. The slurry was then agitated for 30 minutes to insureslaking completion before being screened through a 140 mesh screen. Theslurry was then transferred to 5 liter autoclave and tested for limeavailability in accordance with ASTM method C25. The autoclave is fittedwith an outside heating element contained in an insulated jackethousing. The autoclave is also fitted with a variable speed magneticdrive for stirring the slurry during reaction. Approximately 109.6 gramsof ultra fine fluxed calcined diatomaceous earth was weighed and addedto 750 ml of hot water (concentration of ˜1.22 lb/gallon). The silicaslurry was heated for approximately 10 minutes, to near boiling, thenadded to the screened and tested lime slurry. The exact amount of silicaslurry added to lime slurry was determined by the lime availability suchthat a mol ratio of 1.35 mol CaO/SiO₂ would be maintained. The totalslurry volume was also adjusted to a final concentration of 0.425lb/gallon. The high pressure vessel was then closed, sealed, andconnected to an automated heating/cooling control system (RX 330). Thecontents of the autoclave were under constant agitation via the magneticdrive motor mentioned above.

The high pressure reactor was heated by an externally jacketed heatingelement. The autoclave was continuously agitated at a constant speed of338 rpm. The reactor was heated for approximately 100 minutes in orderto reach the target temperature of 245° C. (473° F.). The temperaturewas maintained at 245° C. for 2 hours, after heating to the targettemperature was accomplished, with the use of the heating/coolingcontroller. At the end of the reaction, the “quenching” water wasflushed through the cooling coil built inside the autoclave. Thiscooling process was maintained until the inside vessel temperaturereached approximately 80° C. (approximately 30 minutes). At which point,the vessel was opened and the reaction products were transferred to aholding vessel for storage. A portion of the resultant slurry was driedin a 105° C. oven for 12 hours. During the drying process, the slurryformed hard lumps, which had to be broken up through the use of a mortarand pestle. The now powdered, dry product was brushed through a 140 meshscreen to insure product uniformity when testing. The pigment in thisexample was designated 5XPC 12. The test carried out on the dry powderwere as follows:

-   -   1) X-ray diffraction analysis    -   2) Scanning Electron Micrograph (S.E.M.)    -   3) Brightness    -   4) Percent Water Absorption    -   5) Air Permeability (Blaine Method)    -   6) pH

For the air permeability test, two numbers are reported. The first isthe weight in grams of powder required to fill the capsule and is anindication of the “bulk density” of the powder. The second is the timein seconds for a controlled volume of air to pass through the compressedpowder inside the capsule and is an approximate measure of the“structure” of the particle.

The process conditions are given in Table 1a and the pigment propertiesare given in Table 1b. TABLE 1a Process conditions of 5XPC 12 Concen-Average Reaction Mol Ratio tration Temperature Pressure Time Batch #(CaO/SiO₂) (lb/gallon) (° C.) (psi) (hours) 5XPC 12 1.35 0.425 245 4562.0

TABLE 1b Pigment Properties of 5XPC 12 Air Air Water PermeabilityPermeability GE Brightness Absorption Blaine Wt. Blaine time Batch # (%reflectance) (%) (g) (sec.) 5XPC 12 96.4 880 0.35 81.8

The x-ray diffraction pattern of this novel, multiphase calcium silicatehydrate is given in FIG. 1. This product (identified as 5XPC 12) gave aunique x-ray pattern. The pattern indicated that the powder had onemajor phase and one minor phase. The summary of the characteristic“peaks” is shown in Table 1c.

The major peaks for phase I were found to indicate the presence ofcalcium silicate hydroxide—Foshagite—(Ca₄(SiO₃)₃(OH)₂) with major peaksat d(Å)=2.97, d(Å)=2.31 and a minor peak at d(Å)=5.05. For phase II, thex-ray diffraction pattern indicated the presence of calcium silicatehydrate—Xonotlite—(Ca₆Si₆O₁₇(OH)₂) with major peaks at d(Å)=3.107,d(Å)=1.75 and a minor peak at d(Å)=3.66. Thus I obtained a novelcombination of Foshagite and Xonotlite from a single reaction. TABLE 1cX-ray diffraction peak summary for 5XPC 12 Crystallochemical d-spacingd-spacing d-spacing Common Name Formula (Major) (median) (Minor)Foshagite CaO₄(SiO₃)₃(OH)₂ d = d = d = (Phase I) (Major) 2.97 Å 2.31 Å5.05 Å Xonotlite Ca₆Si₆O₁₇(OH)₂ d = d = D = (Phase II) (Minor) 3.107 Å1.75 Å 3.66 Å

The S.E.M. pictures at 10,000 times and 2000 times magnification aregiven in FIGS. 2 and 3, respectively. The high magnification S.E.M.clearly shows the fibrous structure of Foshagite and a small fraction of“rod” or “ribbon” like, tubular structures of Xonotlite. The diameter ofthe Foshagite “fibers” ranges from 0.1 to 0.2 microns while the lengthranges from 1 to 5 microns. The Xonotlite particles had diameters in therange of 0.1 to 0.3 microns and a length in the range of 1 to 3 microns.

The low magnification S.E.M. depicts the three dimensional structure ofthe secondary particles of calcium silicate hydrates. The structureappears to have been formed by an interlocking of the primary “fibrous”crystals and some inter-fiber bonding due to hydrogel of silica formedduring the initial stages of hydro-thermal reaction. Because of thesetwo main reasons, the secondary particles are fairly stable and do notsignificantly lose their 3-d structure when subjected to process shear.In addition, these particles also seem to withstand the pressureencountered during the calendering or finishing operations integral topapermaking. The median size of the secondary particles as seen, rangesfrom 10 to about 40 microns.

In order to evaluate this pigment in paper, handsheets were prepared forevaluation. Handsheets were prepared using the 5XPC 12 product sample inorder to evaluate the papermaking characteristics of the pigment. Theprocedure included preparation of a standard pulp slurry made up of 75%hardwood and 25% softwood. Both pulp sources were beaten separately, ina Valley Beater, to a specific Canadian Standard Freeness of 450±10 inaccordance with TAPPI test methods T-200 and T-227. Handsheets wereformed from the prepared stock, on a 6″ British handsheet mold, inaccordance with TAPPI test method T-205. The exceptions to the standardmethod were as follows. Since the goal of producing these handsheets wasto test filler performance, some filler was incorporated into thehandsheets at various replacement levels (usually 15%, 20%, and 25%). Inorder to achieve comparability between different levels, a constantbasis weight was achieved via a reduction in fiber content. Thus, a 25%filled sheet would contain only 75% of the fiber that the unfilled sheethad. The next variation on the standard test method was the addition ofretention aid. A retention aid (Percol 175) was added to hold the fillerin the sheet until the sheet had dried completely. All other handsheetformation components were kept consistent with TAPPI test method T-205.

The handsheets were tested in accordance with TAPPI test method T-220,with one exception. Instead of using a 15 mm sample for testing tensile,a 25.4 mm sample was used and the tensile index calculations werealtered accordingly. The handsheets were ashed in accordance with TAPPItest method T-211.

Paper handsheets were tested for the following properties:

-   -   1. Opacity    -   2. Sheet Scattering Coefficient    -   3. Filler Scattering Coefficient    -   4. Brightness    -   5. Sheet Bulk (Basis Weight/Caliper ratio)    -   6. Sheet Stiffness    -   7. Sheet Porosity    -   8. Sheet Smoothness    -   9. Sheet Tensile Index

A standard alkaline filler, precipitated calcium carbonate (SMI AlbacarHO), was used as a reference material to gauge product performance. Theresults of the handsheet evaluation are given in Tables 1d and 1e. TABLE1d Optical property performance of handsheets containing 20%(interpolated) 5XPC 12 and pulp only. Sheet Filler Scattering ScatteringBrightness Coefficient Coefficient Pigment (ISO) Opacity (ISO) (cm²/g)(cm²/g) 5XPC 12 90.56 90.88 835.21 3077.24 Pulp Only 85.73 73.19 274.8NM Improvement +5.6% +24.2% +203.9% — over pulp

TABLE 1e Strength property performance of handsheets containing 20%(interpolated) 5XPC 12 and pulp only. Stiffness Porosity (Gurley(sec/100 cc Pigment Units) Bulk (cm³/g) air) 5XPC 12 150.74 1.73 64.91Pulp Only 137.15 1.40 51.94 Improvement +9.9% +23.3% +25.0% over pulp

TABLE 1f Optical property performance of handsheets containing 20%(interpolated) 5XPC 12 and 20% (interpolated) PCC. Sheet FillerScattering Scattering Brightness Opacity Coefficient Coefficient Pigment(ISO) (ISO) (cm²/g) (cm²/g) 5XPC 12 90.56 90.88 835.12 3077.24 PCC 90.4488.69 709.84 2474.48 Improvement Even +2.47% +17.66% +24.36% over PCC

TABLE 1g Strength property performance of handsheets containing 20%(interpolated) of 5XPC 12 and 20% (interpolated) PCC. Porosity StiffnessTensile Bulk (sec/100 cc (Gurley Index Pigment (cm³/g) air) Units)(Nm/g) 5XPC 12 1.73 64.91 150.74 31.17 PCC 1.55 22.24 107.54 27.95Improvement +11.56% +191.9% +40.17% +11.53% over PCC

EXAMPLE 2 (5XPC—27 pigment sample)

This novel, multiphase calcium silicate hydrate was formed byhydro-thermal reaction of lime and silica. The CaO/SiO₂ mol ratio usedfor this new product was 0.85, the final slurry concentration was ˜0.8lb/gallon, the reaction temperature was 190° C., and the reaction timewas 2.5 hours. A summary of these conditions is given in Table 2a.

A totally new product was formed using a new set of reaction conditions.First, the CaO/SiO₂ mol ratio was adjusted to 0.85, the reactiontemperature was set to 190° C., the slurry concentration was increasedto 0.75 lbs/gallon, and the reaction time was increased to 2.5 hours.The product of this example was designated 5XPC 27.

A summary of the reaction conditions is given in Table 2a: TABLE 2aProcess conditions of 5XPC 27 Concen- Average Reaction Mol Ratio trationTemperature Pressure Time Batch # (CaO/SiO₂) (lb/gallon) (° C.) (psi)(hours) 5XPC 27 0.85 0.75 190 163.5 2.5

The resulting calcium silicate hydrate was tested for pigmentbrightness, water absorption, Blaine air permeability and density, andpH. Both X-ray diffraction and Scanning Electron Micrograph analyseswere also performed on this product. The pigment properties are given inTable 2b. The pigment was evaluated for its performance in paper byincorporating it into handsheets as in example 1. The results of thehandsheet work are given in Tables 2d and 2e. The X-ray diffractionpattern is given in FIG. 4. The S.E.M. pictures at 10,000 and 2000 timesmagnification are given in FIGS. 5 and 6, respectively.

The calcium silicate hydride formed under these conditions hadsubstantially lower brightness and water absorption characteristics thanTiSil Brand CSH set forth in Example 1. However, it gave much highersheet bulk and sheet permeability characteristics. The pigmentproperties of my novel 5XPC 27 pigment are given in Table 2b. It appearsthat this product provided a much higher sheet bulk. Also, the sheetpermeability of this new product was higher than the Foshagite-Xonotlitecomplex as described in Example 1. TABLE 2b Pigment Properties of 5XPC27 Air Air Water Permeability Permeability G.E. Brightness AbsorptionBlaine Wt. Blaine time Batch # (% reflectance) (%) (g) (sec.) 5XPC 2791.2 360 0.5 17.0

As the mole ratio of CaO/SiO₂ was reduced to ˜0.85 and the reactiontemperature was lowered to 190° C., I discovered another unique anduseful multiple phase calcium silicate hydrate material with a distinctand unique X-ray diffraction pattern. The X-ray diffraction analysisrevealed this product to be a mixture of Riversideite [Ca₅Si₆O₁₆(OH)₂]and Xonotlite [Ca₆Si₆O₁₇(OH)₂]. The X-ray diffraction pattern is givenin FIG. 4. The pattern indicated that the powder had one major phase andone minor phase. The peak summary is shown in Table 2c. TABLE 2c X-raydiffraction peak summary for 5XPC 27 Common Crystallochemical d-spacingd-spacing d-spacing Name Formula (Major) (Median) (Minor) RiversideiteCa₅Si₆O₁₆(OH)₂ d = d = 3.58 Å d = 2.80 Å (Phase I) (Major) 3.055 Åxonotlite Ca₆Si₆O₁₇(OH)₂ d = d = 4.09 Å d = 2.50 Å (Phase II) (Minor)3.056 Å

The major peaks for phase I were found to indicate the presence ofcalcium silicate hydrate—Riversideite—(Ca₅Si₆O₁₆(OH)₂) with major peaksat d(Å)=3.055, d(Å)=3.58 and a minor peak at d(Å)=2.80. For phase II,the pattern indicated the presence of calcium silicatehydroxide—Xonotlite—(Ca₆Si₆O₁₇(OH)₂) with major peaks at d(Å)=3.056,d(Å)=4.09 and a minor peak at d(Å)=2.50. The pigment also containedtrace amounts of calcite (CaCO₃). The other portion of the slurry wastested for the pigment performance as a filler in paper. The paper wasformed into handsheets and tested using the procedures described inexample 1.

The S.E.M. pictures at 10,000 times and 2000 times are given in FIGS. 5and 6. As can be seen in the 10,000×magnification photograph, theproduct is unlike the previous example. The calcium silicate hydratemixture has fibrous and non-fibrous composition joined possibly by anamorphous portion of silica hydrogel formed during the initial phase ofhydro-thermal reaction.

The 2000×magnification indicates the formation of an irregular globularparticle formed by the fibrous inter-growth of a series of primaryfibrous crystals. The particle size is in the range of 10-30 microns andthe crystals seem to have grown randomly.

This multi-phase (primarily Riversideite and Xonotlite) calcium silicatehydrate gave lower brightness value than that of Example 1. Moresignificantly, this material gave a much lower water absorption (around360% -400%) as well.

To evaluate performance in paper, handsheets were formed using thispigment and then tested as in Example 1. The paper performance resultsare shown in Tables 2d-g.

This product, compared to pulp only, gave substantially higher stiffnessand sheet bulk. Unlike the pigment provided in Example 1, (whereFoshagite was the primary component), this second pigment (whereRiversideite and Xonotlite are present) combination produced a much moreopen sheet, as shown by the low Gurley porosity numbers. The opticalproperties, like brightness, opacity and scattering coefficient of thesheet decreased.

Comparing the performance of this second pigment (with predominantlyRiversideite and Xonotlite present) with an alkaline filler, such asprecipitated calcium carbonate, the sheet stiffness and bulk improveddramatically. The optical properties (sheet opacity, sheet brightness,etc.) of the handsheets decreased, however. The decreased opticalproperties of this new multiphase product were clearly due to the largeparticle size and irregular globular structure as seen in the S.E.M.pictures. TABLE 2d Optical property performance of handsheets containing20% (interpolated) 5XPC 27 and pulp only. Sheet Filler ScatteringScattering Brightness Opacity Coefficient Coefficient Pigment (ISO)(ISO) (cm²/g) (cm²/g) 5XPC 27 87.86 83.35 449.12 1092.42 Pulp Only 85.1974.97 292.1 N/A Improvement +3.1% +11.2% +53.8% — over pulp

TABLE 2e Strength property performance of handsheets containing 20%(interpolated) 5XPC 27 and pulp only. Stiffness Porosity (Gurley(sec/100 cc Pigment Units) Bulk (cm³/g) air) 5XPC 27 225.87 2.46 3.92Pulp Only 136.68 1.47 33.5 Improvement +65.2% +68.0% −88.3% over pulp

TABLE 2f Optical property performance of handsheets containing 20%(interpolated) 5XPC 27 and 20% (interpolated) PCC. Sheet FillerScattering Scattering Brightness Opacity Coefficient Coefficient Pigment(ISO) (ISO) (cm²/g) (cm²/g) 5XPC 27 87.86 83.35 449.12 1092.42 PCC 90.2189.39 738.55 2546.03 Improvement −2.6% −6.76% −39.19% −57.09% over PCC

TABLE 2g Strength property performance of handsheets containing 20%(interpolated) of 5XPC 27 and 20% (interpolated) PCC. Stiffness PorosityTensile (Gurley Bulk (sec/100 cc Index Pigment Units) (cm³/g) air)(Nm/g) 5XPC 27 225.87 2.46 3.92 29.67 PCC 102.11 1.65 13.23 24.77Improvement +121.19% +49.22% −70.39% +19.79% over PCC

Thus, this multiphase combination of calcium silicate hydrate was mostuseful in improving sheet stiffness and sheet bulk. It was alsoexcellent for “opening up” the sheet (lowering the Gurley porosity) formore “breathing.” Due to its excellent stiffness, I refer to thisproduct as “StiSil Brand CSH.”

EXAMPLE 3 Varying Reaction Temperature (XPC 119)

Initially, 39.9 grams of pebble lime was weighed accurately and addedslowly to 1.2 L of water in a beaker with constant agitation. The amountof lime, water, and the rate of lime addition were controlled in aneffort to keep the slurry from boiling due to the exothermic nature ofthe lime slaking reaction. The slaked lime of Ca(OH)₂ was screened in a200 mesh screen. The residual material was then discarded. The filteredCa(OH)₂ slurry was tested by acidic titration to calculate the exactamount of available lime. The slaked lime was then transferred into a 2liter autoclave. Then, 31.06 grams of ultrafine, calcined diatomaceousearth was added to 200 ml of water in order to produce a slurry of0.1553 g/L concentration. This slurry was also preheated with constantstirring and brought to near boiling (near 100° C.). Next, the silicawas added to the autoclave containing the hot slaked lime slurry. Thetotal solids concentration of the CaO+SiO₂ slurry inside the autoclave,at this point was ˜0.5 lbs/gallon. The mol ratio of lime to silica was1.67 CaO/SiO₂. The high-pressure reactor was sealed and then heated byan externally, jacketed, electrical heating element.

The autoclave was simultaneously agitated at a constant speed magneticdrive motor at 600 RPM. The autoclave was heated until a presettemperature of 220° C. was reached. At that point the reactionconditions were held constant by a system controller, RX-32. TheCaO+SiO₂ slurry was reacted at a temperature of 220° C. for 120 minutes.At the end of this time, the “quenching” water was passed through acooling system built into the inside of the autoclave. Inside thepressure vessel, steam condensed and the temperature fell rapidly. Thecooling water continued until the vessel reached approximately 80° C.

The silicate slurry was transferred into a holding beaker. The followingdescribes the overall heating/cooling cycle (see FIG. 5):

-   -   Time to temperature˜100 minutes    -   Time at temperature˜120 minutes    -   Time for cooling˜25 minutes

A portion of the slurry was tested for the following properties:

-   -   1) X-Ray Diffraction Analysis    -   2) Scanning Electron Microscope (S.E.M)    -   3) Brightness    -   4) Water Absorption    -   5) Blaine Air Permeability (ASTM/ASTM C204-78a)        -   Sample Weight (g)—Indication of Bulk Density        -   Time (in sec) for a fixed volume of air to pass through the            volume of sample—Indication of particle packing or structure

The reaction conditions and pigment properties are given in Tables 3aand 3b respectively.

EXAMPLE 4 Varying Reaction Temperature (XPC 107)

In this example, all the reaction conditions and parameters wereidentical to example 3 above, except for the reaction temperature wasraised from 220° C. to 233° C. The resultant calcium silicate hydratecomplex was then tested as per the above-described test program and theresultant reaction conditions and pigment properties are given in Tables3a and 3b respectively.

EXAMPLE 5 Varying Reaction Temperature (XPC 124)

In this example, all of the reaction conditions and parameters were keptconstant, as in example 3, except for reaction temperature. The reactiontemperature was raised from 233° C. to 243° C. The calcium silicatehydrate complex formed was tested as in the above examples. The reactionconditions and pigment properties are given in Tables 3a and 3brespectively. TABLE 3a Reaction conditions for Examples 3, 4, and 5.Mole Temp Reaction Ratio Conc. (degrees Time Example # Batch ID(CaO/SiO₂) (lbs/gal) C.) (hours) Example 3 XPC 119 1.67 0.7 220.0 2Example 4 XPC 107 1.67 0.7 233.0 2 Example 5 XPC 124 1.67 0.7 243.0 2

TABLE 3b Pigment properties for Examples 3, 4, and 5. Water BlaineBlaine Absorption Brightness Wt. Time Example # (%) (ISO) (grams) (sec.)PH Example 3 440 94.2 0.5 94 11.6 Example 4 440 96.2 0.45 118.5 10.7Example 5 580 94.9 0.35 94.9 11.5

Note that the mid range reaction temperature of 233° C. produced thehighest brightness material.

EXAMPLE 6 Varying the CaO/SiO₂ mol Ratio (XPC 130)

In this example, all the reaction parameters were kept constant, as inexample 4, except for the CaO/SiO₂ mol ratio. The CaO/SiO₂ mol ratio waschanged to 1.4.

Then, 69.0 g of SiO₂ and 78.0 g of CaO were mixed to give a CaO/SiO₂ molratio of 1.4. The two slurries, CaO and SiO₂ were mixed in theautoclave. The concentration in the autoclave was adjusted by addingwater to 0.7 lb/gal. The reaction was carried out for two hours and theautoclave was cooled and the product was handled as in example 1. Thereaction temperature was kept constant at 233° C. The reaction mixturewas agitated at a constant speed via a magnetic drive motor attached tothe autoclave. The motor was rotated at 600 RPM. The final product wastested for key parameters and the reaction conditions and key pigmentproperties are shown in Tables 4a and 4b respectively.

EXAMPLE 7 Varying the CaO/SiO₂ mol Ratio (XPC 132)

In this example, all the reaction parameters were kept constant as inexample 4, except the CaO/SiO₂ mol ratio was raised to 1.6. Thehydrothermal reaction was carried out using the same cycle of heatingand cooling as in the previous examples and the final product was againtested for key pigment properties. The reaction conditions and keypigment properties are shown in Tables 4a and 4b respectively.

EXAMPLE 8 Varying CaO/SiO₂ mol Ratio (XPC 134)

Here again, the reaction parameters were all held constant, as inexample 4, except for the CaO/SiO₂ mol ratio, which was raised to 1.8.The hydrothermal reaction was carried out using the same cycle ofheating and cooling as in the previous examples and the final productwas again tested for key pigment properties. The reaction conditions andkey pigment properties are shown in Tables 4a and 4b respectively. TABLE4a Reaction conditions for Examples 6, 7, and 8. Mole Temp. ReactionRatio Conc. (degrees Time Example # Batch # (CaO/SiO₂) (lbs/gal) C.)(hours) Example 6 XPC 130 1.4 0.7 233.0 2 Example 7 XPC 132 1.6 0.7233.0 2 Example 8 XPC 134 1.8 0.7 233.0 2

TABLE 4b Pigment properties for Examples 6, 7, 8. Water Blaine BlaineAbsorption Brightness Wt. Time Example # (%) (ISO) (grams) (sec.) pHExample 6 380 94.7 0.45 112 10.9 Example 7 420 94.1 0.45 51.9 11.4Example 8 400 94.7 0.5 57.8 11.7

Note that a CaO/SiO₂ mole ratio of 1.6 produced a calcium silicatehydrate with the highest water absorption capability.

EXAMPLE 9 Varying Reaction Time (XPC 172)

In this example, all the process conditions were kept constant, as inexample 7, except for the reaction time, which was lowered to 1 hour.The calcium silicate hydrate complex was tested as in the previousexamples and the reaction conditions and key pigment properties areshown in Tables 5a and 5b respectively.

EXAMPLE 10 Varying Reaction Time (XPC 173)

In this example, all the process conditions were kept constant, as inexample 9, except for the reaction time, which was raised to 2 hours.The calcium silicate hydrate complex was tested as in the previousexamples and the reaction conditions and key pigment properties areshown in Tables 5a and 5b respectively.

EXAMPLE 11 Varying Reaction Time (XPC174)

In this example, all the process conditions were kept constant, as inexample 9, except for the reaction time, which was raised to 3 hours.The calcium silicate hydrate complex was tested as in the previousexamples and the reaction conditions and key pigment properties areshown in Tables 5a and 5b respectively. TABLE 5a Reaction conditions forExamples 9, 10, and 11. Mole Temp. Reaction Ratio Conc. (degrees TimeExample # Batch # (CaO/SiO₂) (lbs/gal) C.) (hours) Example 9  XPC 1721.67 0.7 233.0 1 Example 10 XPC 173 1.67 0.7 233.0 2 Example 11 XPC 1741.67 0.7 233.0 3

TABLE 5b Pigment properties for Examples 9, 10 and 11. Water BlaineBlaine Absorption Brightness Wt. Time Example # (%) (ISO) (grams) (sec.)PH Example 9  480 92.9 0.5 74 11.1 Example 10 520 96.1 0.45 108.5 11.0Example 11 600 93.3 0.4 135.0 11.2

Note that a reaction time of 2 hours produced the highest brightnessproduct. The longer reaction time of 3 hours produced the greatest waterabsorption values, but at a lower brightness.

EXAMPLE 12 Varying CaO-SiO₂ Slurry Concentration (XPC 136)

In this example, all the reaction conditions were kept constant, as inExample 7, except for the CaO/SiO₂ slurry concentration, which waslowered to 0.4 lb/gallon. To start, 49.6 g of lime was slaked, screened,and titrated for available CaO. Then, 34.2 g of ultra-fine fluxedcalcined diatomaceous earth was slurried. The fluxed calcineddiatomaceous earth slurry was added to the lime slurry to give themixture an initial CaO/SiO₂ mol ratio of 1.6. The reactants were thenplaced in a 2.0 liter autoclave and water was added to bring the finalconcentration of CaO+SiO₂ slurry up to 0.4 lb/gallon. The reactiontemperature was set at 233° C. The autoclave was set and controlledusing a temperature controller for both heating and cooling cycles asshown in FIG. 9. The silica-lime slurry was reacted at 233° C. for twohours. At the end of the reaction, the resulting calcium silicatehydrate was cooled by circulating water through the jacketed autoclave.The resulting mass was transferred to a holding beaker. The product wastested for the same key parameters and with the same methods asdescribed in example 3. The reaction conditions and key pigmentproperties are shown in Tables 6a and 6b, respectively.

EXAMPLE 13

Varying CaO—SiO₂ Slurry Concentration (XPC 138)

In this reaction, all the reaction parameters were kept constant, as inexample 12, except for the CaO+SiO₂ slurry concentration, which wasraised to 0.6 lb/gallon. The product was tested as in Example 3 and thereaction conditions and key pigment properties are shown in Tables 6aand 6b, respectively.

EXAMPLE 14 Varying CaO—SiO₂ Slurry Concentration (XPC 140)

In this reaction, all the reaction parameters were kept constant, as inexample 12, except for the CaO+SiO₂ slurry concentration, which wasraised to 0.8 lb/gallon. The product was tested as in example 3 and thereaction conditions and key pigment properties are shown in Tables 6aand 6b, respectively.

EXAMPLE 15 Varying CaO—SiO₂ Slurry Concentration (XPC 141)

In this reaction, all the reaction parameters were kept constant, as inexample 12, except for the CaO/SiO₂ slurry concentration, which wasraised to 0.9 lb/gallon. The product was tested as in example 3 and thereaction conditions and key pigment properties are shown in Tables 6aand 6b, respectively. TABLE 6a Reaction conditions for Examples 12, 13,14, 15. Mole Temp. Reaction Ratio Conc. (degrees Time Example # Batch #(CaO/SiO₂) (lbs/gal) C.) (hours) Example 12 XPC 136 1.6 0.4 233 2Example 13 XPC 138 1.6 0.6 233 2 Example 14 XPC 140 1.6 0.8 233 2Example 15 XPC 141 1.6 0.9 233 2

TABLE 6b Pigment properties for Examples 12, 13, 14, 15. Water BlaineAbsorption Brightness Wt. Blaine Time Example # (%) (ISO) (grams) (sec.)pH Example 480 93.9 0.45 93.7 11.4 12 Example 460 94.6 0.50 173.0 10.413 Example 560 96.7 0.35 75.1 10.7 14 Example 420 94.2 0.45 45.7 11.6 15

Note that the slurry concentration of 0.8 lb/gallon produced the highestbrightness and the lowest bulk density.

EXAMPLE 16 (5XPC 52)

In this example, the same procedures described in example 1 were used,except that the siliceous raw material was changed. Instead of usingdiatomaceous earth, a source of 100% pure silica was used (trade name:Min-U-Sil). The reaction was carried out at a very low CaO—SiO₂ slurryconcentration of 0.2 lb/gallon. The resultant calcium silicate hydratecomplex was tested for the same key pigment properties as in example 1above. The reaction conditions and key pigment properties are given inTables 7a and 7b, respectively.

EXAMPLE 17 (5XPC 55)

In this example, the same procedures described in example 16 were used(including using the pure silica for a siliceous source). The onlydifference here was that the CaO—SiO₂ slurry concentration was raised to0.4 lb/gallon, and the temperature was kept at 232° C. The calciumsilicate hydrate complex formed from this reaction was tested as inexample 16 above. The reaction conditions and key pigment properties aregiven in Tables 7a and 7b. TABLE 7a Reaction conditions for Examples 16and 17. Average Reaction Mol Ratio Conc. Temp. Pressure Time Batch #(CaO/SiO₂) (lb/gallon) (° C.) (psi) (hours) 5XPC 52 1.31 0.25 245 490 25XPC 55 1.31 0.4 232 387 2

TABLE 7b Pigment Properties Examples 16 and 17 Air Perm. Water Air Perm.Blaine G.E. Brightness Absorption Blaine time Batch # (% reflectance)(%) Wt. (g) (sec.) 5XPC 52 96.2 920 5XPC 55 95.1 840

EXAMPLE 18 Sodium Silicate (5XPC 57)

In this example, all the reaction procedures were kept constant as inexample 1. The only difference was the addition of a different siliceousraw material source. Here, 20 parts of the fluxed calcined diatomaceousearth were replaced by liquid sodium silica Na₂O—SiO₂ ratio of 1:3 (P.Q.“N” product). The overall CaO/SiO₂ mol ratio was kept at 1.31, theconcentration of the CaO—SiO₂ slurry was kept at 0.5 lb/gallon, and allthe other reaction conditions were kept the same as well. This productwas also tested according to the procedures in example 1. The reactionconditions and key pigment properties are given in Tables 8a and 8b,respectively. TABLE 8a Reaction conditions for Examples 18. Tempera-Average Reaction Mol Ratio Concentration ture Pressure Time Batch #(CaO/SiO₂) (lb/gallon) (° C.) (psi) (hours) 5XPC 1.31 0.5 245 375 2 57

TABLE 8b Pigment Properties Examples 18. Air Air Water PermeabilityPermeability GE Brightness Absorption Blaine Wt. Blaine time Batch # (%reflectance) (%) (g) (sec.) 5XPC 57 97.0 680 0.35 57.5

Note that the most significant difference between this product and theprevious example is the high brightness values produced.

EXAMPLE 19 (TiSil Brand CSH vs. PCC)

Application of multi phase calcium silicate hydrate complex comprisingpredominantly Foshagite, Ca₄ (SiO₃)₃ (OH)₂ and some Xonotlite,Ca₆Si₆O₁₇(OH)₂ in paper according to the following process conditions.My novel calcium silicate hydrate complex, referred to as TiSil BrandCSH, was applied in paper handsheets. It was compared to commercial PCC(SMI's Albacar(HO)) and a mixture of PCC and approximately 60 lbs. perton TiO₂. The results of the testing are given in Table 9a and 9b. Thegraphs showing the performance of TiSil compared to PCC are given inFIGS. 6 through 13. Improvement by TiSil over PCC is given in Tables 9c.TiSil Brand CSH gave the following improvement at 20% ash and equalbrightness: TABLE 9a Optical property performance of handsheetscontaining 20% (interpolated) TiSil and 20% (interpolated) PCC. SheetFiller Scattering Scattering Brightness Opacity Coefficient CoefficientPigment (ISO) (ISO) (cm²/g) (cm²/g) TiSil 87.2 92.3 858.0 3065.1 PCC90.0 89.0 716.8 2507.0

TABLE 9b Strength property performance of handsheets containing 20%(interpolated) of TiSil and 20% (interpolated) PCC. Stiffness Porosity(Gurley (sec/100 cc Tensile Pigment Units) Bulk (cm³/g) air) Index(Nm/g) TiSil 135.3 1.78 47.5 30.0 PCC 113.4 1.58 26.0 29.0

TABLE 9c Handsheet results for TiSil vs. PCC Opacity +2.13% ScatteringPower of sheet +16.2% Filler Scattering Coefficient +24% Bulk +9%Porosity +220% Stiffness +38.0% Tensile Strength Index +22.0%

The TiSil brand CSH pigment seemed to improve a combination ofproperties, which were heretofore unattainable. For example, if sheetbulk was improved, sheet porosity would usually drop. In addition, ifsheet bulk was obtained by having a larger particle size, opticalproperties would be significantly reduced. With my novel pigment, it isthe unique composition and structure of the pigment that allowsimprovement in key paper properties like higher bulk and lower porosity.

EXAMPLE 20 (TiSil Brand CSH vs. PCC with 60 lb/ton TiO₂)

In this example, the calcium silicate hydrate from example 1 (5XPC12)was compared with a mixture of SMI's Albacar(HO) containing 60 lb/tonTiO₂. The results of the paper testing are placed in Tables 10a and 10b.The graphical representations of the data are given in FIGS. 18 through25. The improvement TiSil gave over the PCC+TiO₂ mixture (@ 20% ashlevel and equal brightness) is given in Table 10c. TABLE 10a Opticalproperty performance of handsheets containing 20% (interpolated) TiSiland 20% (interpolated) PCC + TiO₂ combination. Sheet Filler ScatteringScattering Brightness Opacity Coefficient Coefficient Pigment (ISO)(ISO) (cm²/g) (cm²/g) TiSil 87.2 92.3 858.0 3065.1 PCC with 90.0 89.0716.8 2507.0 TiO₂

TABLE 10b Strength property performance of handsheets containing 20%(interpolated) of TiSil and 20% (interpolated) PCC + TiO₂ combination.Stiffness Porosity Tensile (Gurley Bulk (sec/100 cc Index Pigment Units)(cm³/g) air) (Nm/g) TiSil 135.3 1.78 47.5 30.0 PCC with 113.4 1.58 26.029.0 TiO₂

TABLE 10c Handsheet results - TiSil vs. PCC + TiO₂ combination Opacityby 0.5% Scattering Power of sheet by 3.0% Filler Scattering Coefficientby 4.0% Bulk by 8.2% Porosity by 40.0% Stiffness by 26.0% Tensile by221.0%

Here, TiSil Brand CSH has demonstrated exceptional scattering power forlight, an unusual ability to close up the sheet (higher Gurley porosity)and a significant improvement in sheet bulk, stiffness, and tensileindex.

EXAMPLE 21 (TiSil Brand CSH vs. Bulkite—XPC65)

In this example, the pigment of my invention, namely a calcium silicatehydrate complex (Foshagite-Xonotlite complex) was manufactured under theconditions given in Table 11a. The pigment was tested for brightness,water absorption, Blaine, and pH. The results are given in Table 11b.This product was compared as a paper-making pigment with commerciallyavailable calcium silicate, (Trade name Bulkite). The graphicalrepresentation of the results are given in FIGS. 26-30. The comparisonof the two pigments, XPC-65 and Bulkite at 20% ash is given in Table11c. The improvement over Bulkite at 20% ash (interpolated) is given inTable lid. TABLE 11a Reaction conditions for Example 21. Tem- ReactionMol Ratio Concentration perature Time Example # Batch # (CaO/SiO₂)(lb/gallon) (° C.) (hours) Example XPC 65 1.67 0.71 232 2 21

TABLE 11b Pigment properties for Example 21. Water Absorption BrightnessBlaine Wt. Blaine Time Example # (%) (ISO) (grams) (sec.) PH Example 21420 93.7 0.45 46.2 10.7

TABLE 11c Optical property performance of handsheets containing 20%(interpolated) XPC 65 and Bulkite. Sheet Filler Scattering Scat.Porosity Opacity Coefficient Coeff. Brightness (sec/100 cc Pigment (ISO)(cm²/g) (cm²/g) (ISO) air) XPC - 65 90.9 845.4 3109.6 90.0 42.4 Bulkite84.2 460.9 1273.4 86.4 4.9

TABLE 11d Summary of TiSil Improvement over Bulkite Opacity by 7.2%Scattering Power of sheet by 83.0% Filler Scattering Coefficient by144.0% Brightness by 4.13% Porosity by 770.0%

Once again, this product shows substantially significant improvementover industry standard pigments.

EXAMPLE 22 (XPC 117) Application in Newsprint

In this example, the multi-phase CSH Foshagite—Xonotlite was made by thesame procedure as in Example 1, using the process conditions in Table12a below. TABLE 12a Reaction conditions for Example 22. Tempera-Reaction Example Batch Mol Ratio Concentration ture Time # # (CaO/SiO₂)(lb/gallon) (° C.) (hours) Example XPC 1.67 0.67 224 2 22 117

The product was tested for brightness, water absorption, Blaine and pH.The results are given in Table 12b. TABLE 12b Pigment properties forExample 22. Water Absorption Brightness Blaine Wt. Blaine Time Example #(%) (ISO) (grams) (sec.) pH Example 22 470 95.3 0.45 184.7 10.6

The calcium silicate hydrate complex of this invention was added tonewsprint furnish (20% kraft, 80% TMP). To compare the performance ofthe product of my invention, handsheets were made using commerciallyavailable calcium silicate (Hubersil, JM Huber Co.) and a precipitatedcalcium carbonate (also by JM Huber Co). The newsprint sheets containingthese pigments were tested for the following:

-   -   Sheet bulk, stiffness, porosity, smoothness, brightness, opacity        and several print quality parameters like ink strike through,        show through and overall print through. Sheets were also tested        for the static coefficient of friction.

The actual values, interpolated to 6% ash, are given in Tables 12c and12d. A comparison of the product of my invention and Huber's PCC andHuberSil gave the differences shown in Tables 12e and 12f. Thecorresponding bar graphs at 6.0% interpolated ash are given in FIGS. 31through 39. TABLE 12c Optical property performance of handsheetscontaining 6% (interpolated) TiSil, HuberSil, and Huber Carbonate.Normalized Opacity Ink Show Print Pigment (ISO) Penetration ThroughThrough TiSil 86.29 1.46 4.67 6.13 HuberSil 85.33 1.60 5.14 6.74 Huber86.75 2.46 4.79 7.24 Carbonate

TABLE 12d Strength property performance of handsheets containing 6%(interpolated) TiSil, HuberSil, and Huber Carbonate. Static SheetPorosity Tensile Stiffness Coeff. Smoothness (sec/100 cc Index (Gurleyof (Sheffield Pigment air) (Nm/g) Units) Friction Units) TiSil 15.4025.57 22.08 0.90 159.76 HuberSil 11.93 21.95 24.31 0.90 176.02 Huber11.36 25.32 18.06 0.86 164.06 Carbonate

TABLE 12e Summary of Improvement over Huber Carbonate Opacity −0.53% InkPenetration 40% less (better) Show through 2.0% less (better) Overallprint through 15.0% less (better) Porosity +35.0% (better) Tensile evenStiffness +22% (better) Static coefficient of friction +5.0% (better)

A comparison of my new multi-phase CSH products with Huber's calciumsilicate gave the following: TABLE 12f Summary of Improvement overHuberSil Opacity +1.1 points Ink Penetration 9.0% less (better) Showthrough 9.0% less (better) Overall print through 9.0% less (better)Porosity +29.0% (better) Tensile +16.0% (better) Shefield smoothness10.0% less (better)

Once again, my multi-phase CSH product gives better paper and printingproperties than currently available commercial calcium carbonate andcommercial calcium silicate fillers.

During testing of my novel multi-phase calcium silicate hydrateproducts, conventional industry quality control standards were observed.Brightness was tested by using a GE/TAPPI Brightness Meter, Model S-4.Where applicable, the pH was tested with a pH meter utilizing TAPPImethod T-667. Pulp beating was performed using a Valley Beater accordingto TAPPI Method T-200. Handsheets were produced using a BritishHandsheet Mold according to TAPPI Method T-205. Handsheet testing wasfor tensile strength used a one inch strip and otherwise was conductedaccording to TAPPI method T-220. Where applicable, freeness was testedutilizing a Canadian Standard Freeness tester according to TAPPIstandard T-227. Ashing tests were conducted at 500° C. according toTAPPI Method T-211. Air permeability testing was conducted by Blaine,ASTM Method C204. Available lime was measured according to ASTM MethodC25. For fine paper testing, a standard pulp slurry was made up of 75%hardwood and 25% softwood. Both pulp sources were beaten separately, ina Valley Beater, to a specific Canadian Standard Freeness of 450±10 inaccordance with TAPPI test methods T-200 and T-227. For newsprinttesting, a standard newsprint pulp slurry was made up of 20% softwoodkraft fibers, and 80% thermo-mechanical pulp. Both pulp sources werereceived with Canadian Standard Freeness values of 180 csf ±25. Thisfreeness value was deemed sufficient and no further beating wasperformed on the pulp. For the disintegration of the was performed onthe pulp. For the disintegration of the stock pulp solutions, hot waterwas added to help relax the pulp fibers and prevent fiber clumps in thefinal sheet. Handsheets were formed from the above prepared stock, on a6″ British handsheet mold, in accordance with TAPPI test method T-205.However, since the goal of producing these handsheets was to test fillerperformance, some filler was incorporated into the handsheets at variousreplacement levels (usually 15%, 20%, and 25%). In order to achievecomparability between different replacement levels, a constant basisweight was achieved via a reduction in fiber content. Thus, a 25% filledsheet contained only 75% of the fiber that the unfilled sheet has. Also,a retention aid was utilized to hold the filler in the sheet until thesheet had dried completely. All other handsheet formation componentswere kept consistent with TAPPI test method T-205. Handsheets utilizingtitanium dioxide in fine paper were similarly formed, except that theyrequired double the amount of retention aid as required by the otherfillers. In addition, when TiO₂ was added in conjunction with anotherfiller, it was necessary to first add TiO₂, then add one dose ofretention aid, and then add the filler and a second dose of retentionaid. Handsheets formed for newsprint testing were prepared in a similarmethod to the fine paper handsheets. However, different filler loadinglevels were utilized, and the newsprint sheets were usually loaded at3%, 6%, and 9% filler. The handsheets were tested in accordance withTAPPI test method T-220, except that a 25.4 mm sample was used and thetensile index calculations were recalculated accordingly. Handsheetswere ashed in accordance with TAPPI test method T-211.

In summary, the unique crystalline microfibres produced as a product ofthe reactions described herein exist, in one unique product, as bundlessized from about 10 to about 40 microns, typically occurring ashaystacks or balls. Preferably, individual fibers are about 0.2 micronsin the largest cross-sectional dimension, with lengths of up to 4 or 5microns, so as to have a relatively large L/D ratio.

Importantly, the crystalline microfibers as just described haveadvantageous properties when utilized as a paper filler, particularly inuncoated groundwood, and in coated groundwood, in uncoated fine paper,and in coated fine paper. The aforementioned adsorptive properties helpto adsorb printing ink in the papers. Also, it helps the paper sheetitself to absorb fines, so that it improves overall sheet retentionduring the papermaking process. Overall, final paper products exhibitimproved porosity, improved smoothness, improved bulk, and improvedstiffness. Also, brightness and opacity are maintained or improved.Moreover, the printability of the final product is significantlyimproved, due to the improved ink adsorption.

It is to be appreciated that my unique, light, fluffy adsorptive calciumsilicate hydrate products, and the method of producing the same, and thepaper products produced using such products, each represent anappreciable improvement in the paper production arts. Although only afew exemplary embodiments of this invention have been described indetail, those skilled in the art may find that the processes describedherein, and the products produced thereby, may be modified from thoseembodiments provided herein, without materially departing from the novelteachings and advantages provided.

It will thus bee seen that the objects set forth above, including thosemade apparent from the preceding description, are efficiently attained.Since certain changes may be made in carrying out production of the CSHproducts, and the unique paper products produce therewith, it is to beunderstood that my invention may be embodied in other specific formswithout departing from the spirit or essential characteristics thereof.Many other embodiments are also feasible to attain advantageous resultsutilizing the principles disclosed herein. Therefor, it will beunderstood that the foregoing description of representative embodimentsof the invention have been presented only for purposes of illustrationand for providing an understanding of the invention, and are notintended to be exhaustive or restrictive, or to limit the invention tothe precise embodiments disclosed. The intention is to cover allmodifications, equivalents, and alternatives falling with the scope andspirit of the invention, as expressed herein above and in the appendedclaims. As such, the claims are intended to cover the products,processes, methods, and equivalent processes and methods. The scope ofthe invention, as described herein, is thus intended to includedvariations from the embodiments provided which are neverthelessdescribed by the broad meaning and range properly afforded to thelanguage herein, and as explained by and in light of the terms includedherein, or by the legal equivalents thereof.

1. A paper composition, said composition comprising: an effective amount of a filler, said filler comprising a multiple phase calcium silicate hydrate comprising foshagite and xonotlite, and having peaks in the XRD patterns from the foshagite and xenotlite components in the complex having the characteristic XDR shown in FIG.
 1. 2. A paper composition according to claim 1, wherein said multiple phase calcium silicate hydrate has a water absorption range of at least about 500 percent.
 3. A paper composition according to claim 1, wherein said multiple phase calcium silicate hydrate has a water adsorption range of up to approximately 1000 percent.
 4. A highly absorbent coating formulation mixture for coating on a printing paper substrate, said coating formulation mixture comprising: an effective amount of a multiphasic calcium silicate hydrate, said multiphasic calcium silicate hydrate comprising foshagite and xonotlite having peaks in the XRD patterns from foshagite and xenotlite components with the characteristic XDR shown in FIG.
 1. an aqueous starch solution; a dispersant; and a binder.
 5. A slurry of multiphasic calcium silicate hydrate, said slurry comprising: fibrous primary crystals interlocked in secondary particles of calcium silicate, said primary crystals and said secondary particles having peaks in XRD patterns from the foshagite and xenotlite components having the characteristic XDR shown in FIG. 1; and wherein said interlocked fibrous primary crystals and secondary particles are dispersed in water.
 6. A slurry of multiphasic calcium silicate crystals as defined in claim 5 in which contains the water is present in an amount of 80 percent or more by weight in said slurry.
 7. A slurry of multiphasic calcium silicate crystals as defined in claim 6 wherein at least about 95% of the secondary particles are less than 40 microns in outside diameter.
 8. A slurry of multiphasic calcium silicate crystals as defined in claim 7 wherein at least about 80% of the secondary particles are 10 to 40 microns in outside diameter. 